Abstract: A hydrodynamic foil system for a sensor streamer array includes towing equipment coupled to a survey vessel. The towing equipment includes at least one spreader cable extending substantially transversely to a direction of motion of the survey vessel. A plurality of laterally spaced apart sensor streamers is coupled at respective forward ends thereof to the towing equipment. A plurality of foils disposed on the spreader cable, the foils configured to provide hydrodynamic lift in a vertical direction as the at least one spreader cable is moved through the water. The foils are each rotatable about the spreader cable.

Abstract: Methods, devices, and computer-readable media are provided for accessing seismic data that describes seismic energy that propagated through media, including water and optionally surface or subsurface layers, to measurement locations in the water. The seismic data includes pressure data that describes time-variant pressures at measurement locations in the water. The seismic data may also include velocity data that describes time-variant velocities of particles at measurement locations in the water. The seismic data is processed using wavefield decomposition to reduce an effect of a portion of the seismic energy that reflects off of the surface of the water. The processing is performed in a discrete domain that includes or is the measurement locations. The discrete domain may exclude certain locations or ranges of locations. The processed seismic data may be used to generate a map of any surfaces of the media through which the seismic energy propagated.

Abstract: Techniques are described for determining an optimal resolution for a grid to be used in solving inverse problems. Reference physical fields may be computed based on model data for the computational grid at a starting resolution. Cells in the computational grid may be split in a plurality of iterations to provide finer resolution. The model data may be perturbed by introducing different physical property values to the cells. The physical fields may be calculated based on the perturbed model data. A comparison may be made between the reference physical fields and the calculated physical fields based on the perturbed model data for the purpose of determining whether cell splitting should continue.

Abstract: Techniques are described for determining particle displacement or particle velocity data from particle acceleration measurements. In an embodiment, an apparatus comprises an interface configured to received particle acceleration data, one or more processors, and one or more storage media. The one or more storage media store instructions for determining one or more of particle velocity data or particle displacement data, based upon the particle acceleration data, by processing the particle acceleration data using a filter that at least approximates a Wiener filter and that uses one or more damping factors selected to provide stability in the presence of noise in the particle acceleration data.

Abstract: System for controlling cables and streamers in a seismic tow arrangement comprising at least one deflector (13) connected to one side of a tow vessel (10) via at least one wire (12), leading or the like, wherein the deflector is located in a position at a distance perpendicularly to the direction of movement (5) of the tow vessel, the vessel being equipped with a navigation system for measuring the position of the vessel. The system is characterised by comprising a command unit and a number of control units, where the control units are located on at least some of the streamers and are adapted to measure and report about their positions, that the command unit comprises means for receiving the position information from each individual control unit and calculation of possible deviations from predetermined positions, and that the system comprises means for changing the position of the streamers for re-establishing the positions of the control units.

Abstract: System for controlling seismic arrays comprising at least one deflector coupled to one side of the towing vessel through at least one wire, lead-in or similar, the detector being positioned at a distance perpendicular to the vessel's direction of movement, the vessel being provided with a navigation system for measuring the position of the vessel. The vessel comprises calculation means for, on the basis of the vessel's position, calculating deviations in vessel's position from a predetermined path. The wire is coupled to the vessel through control organs, e.g. a winch, adapted to vary the wire length from the vessel to the deflector. The control organs are coupled to the calculation means for adjusting the wire length based on the deviations in the position of the towing vessel, thus to avoid corresponding deviations in the movements of the deflector.

Abstract: Collapsible depth controller for mounting in relation to seismic cables or similar devices, comprising two wings, each being rotatably connected to a main body relative to a first axis of rotation perpendicular to the longitudinal direction of the depth controller, to be folded into an adapted room in the main body of the depth controller. The depth controller comprises a first motor for rotation of an at least partially cylindrically shaped cam plate or mushroom cam relative to its axis, the axis essentially corresponding to the longitudinal axis of the depth controller, said cam plate comprising at least one path or cam which along at least part of its length has an angular extension relative to the axis of the cam plate, at least one cam follower engaging into said cam plate and comprising a first coupling device for rotatable connection to the wings, where the first coupling device is positioned at a chosen distance from the first rotational axis of the wing.

Abstract: A drilling riser for use at great sea depths for drilling of wells in the seabed using a drill string, with the drilling riser arranged to be connected between a wellhead at the seabed and a vessel, and arranged for use with a drilling fluid with sufficiently high density to balance the fluid pressure from the geological formations, with a sensor arranged to detect the level of the drilling fluid's level in the drilling riser, and a return riser pipe with an adjustable return riser pump. The return riser pipe extends up to the vessel, from an outlet on the riser, from a depth which is substantially below the sea surface, and at the same time at a height substantially above the seabed.

Abstract: A riser tube tower for stabilizing riser tubes extending from respective wellheads associated with a seabed frame on the seabed to a platform, preferably a tension leg platform, at the sea surface. The riser tube tower includes vertical wires connecting the platform with the seabed frame. Horizontally disposed guide plates are fixed in position at one or more levels of the tower. Vertically movable shuttle plates are located in the vertical spaces over, between, and under the guide plates. The vertical wires and riser tubes pass through spaced apertures in the guide plates and the shuttle plates. The apertures in the shuttle plates are aligned with respective apertures in the guide plates. Bushings are disposed in the apertures of the guide plates and the shuttle plates for protecting the guide plates and shuttle plates from the riser tubes and wires, and for reducing friction therebetween. Elevator devices move the shuttle plates vertically above, below, or between the guide plates.

Abstract: A method and apparatus for monitoring production mineral reservoirs, the method comprising: permanently installing a geophone in a borehole; generating a first set of seismic waves; receiving a first set of seismic data with the geophone; recording the first set of data of said receiving a first set of seismic data; generating a second set of seismic waves after sufficient time has passed for conditions in the reservoir to have changed from the generating a first set of seismic waves; receiving a second set of seismic data with the geophone; and recording the second set of seismic data of said receiving a second set of seismic data. A method and apparatus for installing instruments below the surface of the earth, the method comprising: drilling a borehole with a drill apparatus inserting an instrument in the borehole; and permanently fixing the instruments in the borehole.

Abstract: A system and method are provided for converting an electrical signal to an optical signal for a fiber optic system. The electrical signal produced by a sensor (10) based upon a parameter being measured is connected across a material (12, 34, 40) that changes dimension responsive to an applied electrical signal. An optical fiber (14, 30, 38) is coupled to the material (12, 34, 40) where dimension changes of the material (12, 34, 40) produce strain in the optical fiber (14, 30, 38). This strain is operable to affect light traveling through the optical fiber (14, 30, 38) to produce an optical signal for a fiber optic system. In one embodiment, the sensor (10) can be a geophone sensor that produces an electrical signal proportional to motion of the geophone sensor. In another embodiment, the sensor (10) can be a hydrophone sensor that produces an electrical signal proportional to acoustic pressure incident on the hydrophone sensor.

Abstract: A system for towing equipment at sea comprises a main vessel adapted to tow the equipment in a given direction of movement. At least one active deflector is disposed behind and on each side of the main vessel for pulling at least part of the towed equipment transversely in relation to the direction of movement of the main vessel. At least one support vessel is connected to each deflector for assisting the deflector in pulling at least part of the towed equipment transversely in relation to the direction of movement of the main vessel, and for assisting the main vessel by providing additional towing force to the towed equipment. The additional towing force provided by the support vessel is essentially parallel in direction to the force provided by the main vessel. A cable connects each support vessel to the associated active deflector for supplying one or more of power and control signals from the support vessel to the associated deflector. At least one wing is attached to each deflector.

Abstract: A deflector for towing behind a vessel, especially for use in relation to seismic surveys, being adapted to pull equipment to a transversal position in relation to the moving direction of the vessel, comprising at least one connection point for connecting, through wires or similar, to the vessel and the equipment to be towed. Two or more deflector wings are adapted to provide the deflector with a lifting force transversally in relation to the moving direction of the vessel, at least one of the wings being provided with a rotating cylinder positioned in front of the wing adapted to increase the lift of the deflector wing, and a drive unit for driving the rotating cylinder with corresponding devices for power supply.

Abstract: A mooring system provides a bridle having a star-like shape that is useful for mooring a single vessel or for mooring two or more vessels relative to one another. In general, the mooring system provides a mooring bridle formed of a plurality of anchor connections spaced about a central mooring position. Each anchor connection includes an anchor having a passageway therethrough and an anchor line threaded through the passageway. An anchor buoy is connected to each end of the anchor line; and a bridle line connects the anchor buoys. Adjacent anchor connections share a common anchor buoy and are, thus, interconnected. The length of the bridle lines are less than the distance between the anchors so that the diameter of the circle formed by the bridle lines is less than that formed by the anchors. Vessel lines attached to the anchor buoys extend to the central mooring position for attachment of a tender vessel thereto.

Abstract: A process comprising: fixing a first end of a tendon to an anchor; lowering the anchor to the sea floor; securing the anchor to the sea floor; fixing a second end of the tendon to the platform. A tendon comprising: a flexible line that extends from the TLP to the anchor, wherein the flexible line comprises a top end and a bottom end; an attacher of the top end of the flexible line to the TLP; and an attacher of the bottom end of the flexible line to the anchor. A platform comprising: a platform for floating on the surface of the sea; an anchor for attachment to the sea floor; and a flexible tendon for securing the platform to the anchor.

Abstract: A device (10) for connecting a towed seismic streamer (6) to a lead-in towing cable (7) and to a towing wire (8) is provided. The device (10) comprises a first connecting part (11) with coupling means (11A) for connecting to the foremost end of the streamer (6), a second connecting part (12) with coupling means (12A) for connecting to the end of the lead-in towing cable (7), and an intermediate part (15) having two connecting points (16, 17) for rotatable connection with the first and second connecting parts (11, 12), respectively. The device (10) also comprises a rotatable fastening member (20) for connecting to the towing wire (8) and a flexible conducting means (21) between the opposite ends of connecting parts (11, 12) for electric connection between streamer (6) and lead-in towing cable (7). The angles between the streamer (6), the lead-in towing cable (7), and the towing wire (8) are variable within limits.

Abstract: Processes are described for providing a data set useful for performing analysis of reflection attribute variation among traces in a window of three-dimensional seismic data, wherein the traces have a reflection point assigned thereto and wherein the traces represent recordings from shot-receiver pairs having various azimuth angles. According to one embodiment, the process comprises: assigning an offset value to a plurality of traces; fitting a substantially conical surface having a major and a minor axis to the data of the traces within the window, wherein: the major axis of the cone represents the azimuth direction having the lowest variation in the reflection attribute, and the minor axis of the cone represents the azimuth direction having the highest variation in the reflection attribute; assigning a coordinate set to the surface, wherein the coordinate set is related to a survey geometry of the data; and comparing the reflection attribute variation as a function of offset and azimuth.

Abstract: Device for the adjustment of buoyancy of a seismic cable comprising a main part (1) adapted to firm, integrated mounting into a chosen point in the length of the cable, the main part (1) comprising fastening means (3,4) for one or more weight or buoyancy elements (2) and one or more exchangeable weight or buoyancy elements (2) adapted to being mounted into the main part (1).

Abstract: A process comprising: attaching a first end of a chain to the tendon; securing a second end of the chain to the platform. A mechanism comprising: a chain which is attached to the tendon; and a stopper for attaching the chain to the platform. A tension-leg platform (TLP) comprising: a platform for production operations which floats on the surface of the sea; an anchor which attaches to the sea floor; a flexible tendon which connects to the anchor on the sea floor; and a mechanism for attaching the flexible tendon to the platform.

Abstract: A process comprising: generating a stabilizing moment, before the platform is secured and tensioned to the sea floor, wherein the generating vertically aligns the central axis of the TLP; and reducing the size of the TLP in the wave zone, after a tendon of the platform is secured to the sea floor. A device comprising: a generator of a stabilizing moment, before the platform is secured and tensioned to the sea floor, wherein the generator vertically aligns the central axis of the TLP; and a reducer of the size of the TLP in the wave zone, after a tendon of the platform is secured to the sea floor.